Mushroom and herb polysachariides as alternative for antimicrobial growth promotors in poultry

Summary

Keywords : mushroom and herb polysaccharides, antimicrobial growth promoters, chickens

Antibiotics are widely used as therapeutics agents and also as growth promoters in poultry production. The possibility of developing resistant populations of bacteria and the side effects of using antibiotics as growth promoters in the farm animals has led to the recent EU-ban on the use of several antibiotics as growth promoters in poultry diets. Therefore, there is an intensive search for alternatives such as probiotics, prebiotics and other feed additives. Immuno-active polysaccharides derived from two mushrooms, Tremella fuciformis ( TreS ) and Lentinus edodes ( LenS ), and the herb Astragalus membranacea Radix ( AstS ), seem to be potential alternatives for antimicrobial growth and health promoters. These products were considered to play an important role in strengthening the animals' defense system by improving the physical conditions of gut ecosystem and enhancing functions of the immune system of chickens. The results presented in this dissertation demonstrated that intact mushroom and herb materials and their polysaccharide extracts showed differences in their physico-chemical properties, therefore, these products showed differences in fermentability and led to significant shifts in the bacterial community when fermented in vitro . These medicinal mushroom and herb materials, particularly their polysaccharide extracts, show promise in altering microbial activities and composition in chicken ceca. The polysaccharide extracts showed a slightly significant effect on growth performance and had no effects on weights of immune and GIT organs in normal broilers. However, the polysaccharide extracts significantly enhanced body growth and manipulated cecal microbial ecosystem such as viscosity and microbial species in Avian mycoplasma Gallisepticum infected chickens. And potential beneficial bacteria were significantly increased by the polysaccharide extracts. The polysaccharide extracts showed significant effects on body growth, immune responses as well as growth of immune organs and development of GIT fragments in coccidian-infected chickens, and particularly when they were used in conjunction with vaccine. The use of the mushroom and herb polysaccharide extracts might enhance T-cell immune responses, characterized by IFN- and IL-2 secretion, against coccidiosis in chickens. Supplementation of mushroom and herb extracts resulted in enhancement of resistance toE. tenella probably by enhancing both cellular and humoral immune responses against E.tenella in chickens.